Variable drive clutch for stitch control



L. M. RABINOWITZ VARIABLE DRIVE CLUTCH FOR STITCH CONTROL Filed Sept. 21, 1948 Jan. 9, 1951 2,537,280

2 Sheets-Sheet 1 I 55 52 31 43 BY 57 0 5; 1 19 4. 2/ A 59 A fli'TOH/VE).

Jan. 9, 1951 L. M. RABlNOWlTZ 2,537,280

VARIABLE DRIVE CLUTCH FOR STITCH CONTROL Filed Sept. 21, 1948 L ,2 Sheets-Sheet 2 IN VEN TOR.

Patented Jan. 9, 1951 i kin E CLI'I' (if! roe L'o'uis M. nab-mower, Brook-1mm. asi'siitr ,jtoLouis M. Itabinowitg Foundatiom Inc Doier, Deli, a, corporationof Dela-ware Apiii'sfiidn 'seimeniser 21, 'i-si fs, swarm. "sofa-31 5 "Claims. (01. #4 12525) This invention Treiat'es to "stitching or sewing m'achines, and more partichlarlir to novel means for varying the length of "adjacent stitches in e seam.

The-invention is particnlarlyapplicableto seaiii stitching apparatus in which 'aseam is formed in an article, as for example a folded tap'e, and fastener means or the -1ikesecured thereto in pockets formedat intervals-along the seam. *If

the-seam stitches are'closeiy spaced,'it'-is desirable to lengthen the stitch length when the "seam crosses arms of the wire lo'o'ps'of the fasteners, which, for example, may' be wire hooks or eyes which are "disposed within the pocket's "aforesaid.

In such apparatus, a suitable fridtion rell'er is used to draw the article "lengthwise beneath 'the stitching mechanism forming the seam. The

roller is rotated 'step-by-step to draw the tape under tension from 'a fedsource, --'with the :stitch- 'ing*meansforming a stitchwhiie'the tape is at restbetween successive -stitc'h'es. 1

In order to vary the stitch length, 'the present invention provides novel means for selectively imparting a greater than-normal'o'r less-thannormal rotation to the-roller where it isdesir'ed to form longer or shorter stitches, respectively. A preferred means for accomplishing this result is a novel'- clutch and an associated cam actuate'd clutch operator. v

Specifically, the aforementioned stepping means drives theroller'through a variable stroke clutch. This clutch comprisesadrivingmember attached to the "stepping means "and a driven member integral 'with "or 1 seciiied to the roller.

Thetwo members carry cooperatingteeth having With the foregoing in 'mind, anobject of the invention is to-- provide --nove1 means for varyihg the =stroke'"of" a step by-step "actuated I rotatable member.

An-other object is "-to T provide a -novel stitch iengthselectorandcontroller for seam stitching apparatus.

25 renews,

iIiGVel faitiifes d'f t-he invention will be apparent from the foli Wing description anh the ao'conrpanyin'g ere-wing. fI'n the arming:

l f-i's a per"tia"'1-"p1an view of apparatus in- 6 corpora-ting *the invention, showing the clutch 'in fone position. A

I Fig. 2 1s a View similar *to erg. showing *eh'ztc n anothe'r piisition.

Fig. 8 is" a left 'en'd elevationvies/"affine clutch 10 and its oper'a t'in "ecl'ia-n-ism.

Fig 4 i -avert cal 's'ecticnal viewpn the line r of Fig. -'1, seekin irl the direction "or the 'HJIiIOWS a --Fig. -5- is a perspective vi'w 'of "acIntch-"operatii 'igs ifi anid are elevation vi'e'Ws-df the driving and driven elements, i rSptiVly, 'Of "the old-till. Fig. 8 is a sectional lodedview of the cliith alongthe iiii'es B= 8 Figs-6a ta 1 I 0 are enargedpartimside 1evation -iliefvi's' cif the eiuteh elemerits in two difier'eii-t pe-swans,

Fig. 171 is wperspetiveview of a'stitched artiie showin a h'aving stitches 6f 'difier'en t indicated at M. The rotation of heif t liii 'l mmitheilbf H w. r A

a portion 'of the peripheral surface of which has teeth" -therec5n) is "mounted adjacent g'ear' il for oscillating freely aboiit shaft l 3,"'-a pawl 92 is indiififa On a 15iv6t b61t 9 3 extending laterany r5 from one side of gear 9| the ndse ea dr pavnsz These, and other objiet's, edeem Zs aria s; a step e uarto tne widtn era gearmm on gear rotate with shaft I3 by means of a pin 26. The

outer end of sleeve 24 has an axially elongated, diametric slot 21 of a width slightly less than the diameter of shaft I3 (Figs. 4, 7 and 8). Sleeve 24 has a length less than that of bore 28 of driven member 22, so that a space is left in the outer end of bore 28 to receive the cylindrical hub 3| of driven member 2|. The hub has a diametrically opposite pair of arcuate extensions 32 fitting in slot 2! and over the end of shaft I3. Hub 3| is thus slidable axially in bore 28 and over shaft I3 while being drivingly connected to rotate with the shaft by extensions 32 engaged in slot 2?.

Clutch members 2|, 22 carry circumferentially spaced, cooperating teeth or jaws 33, 34, respectively. It will be noted that the spacing of the clutch teeth on either member is substantially twice the circumferential width of the teeth on the other member. The teeth are secured to the respective members by countersunk studs 36, 31 respectively. Teeth 33 have forward, or driving, sloping surfaces 43 which mate with corresponding surfaces 44 of teeth 34. The described arrangement provides for member 2| to impart a shorter or longer rotation stroke to member 22 in accordance with the relative axial positions of members 2| and 22.

Axial adjustment of clutch members 2|, 22 is accomplished in the following manner. A hub member 46 is shrunk, press-fitted, or otherwise secured in the bore 41 of member 2|, and has a reduced section 48 and an enlarged head 49. A fork formed as a perpendicular extension of a link 52, fits over section 48 inwardly of head 49. Link 52 carries spaced studs 53 engaged in slots 54 of a second link 55. Studs 53 and slots 54 provide for adjustment of the combined length of links 52 and 55.

The end of link 55 has an aperture 56 which loosely fits a stud 5? carried by a cam lever 58. Lever 58 is pivoted to a bracket 59 and carries a stud 6| over which is hooked one end of a spring 62 connected by an eyebolt 63 to a fixed support. pull clutch members 2|, 22 further apart. The free end of lever 58 carries a roller 55 engaging a discontinuous cam III on one face of a spur gear 66 secured to rotate with shaft |2. Lever 58, carrying the roller 65, is maintained aligned properly with cam I0 by virtue of a forked extension 61 fitting over shaft I2.

The cam I9 is arc-shaped, and extends through more than 180 degrees of arc. It decreases uniformly in thickness from a thick end II to a thin end 22. End II has a slope I3 and a perpendicular surface I4. End I2 has a slope I6. Cam I0 is secured to gear 66, with either surface of the cam engaging the gear, by means of countersunk studs TI, TI.

Movement of lever 58 to the left under the influence of spring 62 is limited by a stud I8 in a bracket 8| on ,the lever. Stud i8 engagesa stop 82, and is locked in adjusted position by a lock nut 83. It should be noted that stud I8 may be Spring 62, through lever 58, tends to adjusted to limit the amount of engagement of roller 65 Wih cam 10, by limiting leftward movement of lever 58. If desired, stud I8 may be so adjusted as to maintain the roller 65 out of contact entirely with cam Ill.

The operation of the mechanism is as follows. Assuming that stud I8 is so adjusted that roller 65 does not engage cam I0, shaft I2, through ratchet device I4 imparts a stepping motion to shaft I3. Through clutch 29, this stepping motion imparts uniform rotational steps to clutch driven member 22. This pulls tape I5 to the right (Fig. 3) by an equal amount during each step. While driven member 22 is at rest between steps, the stitching means makes a stitch in tape I5. Under the given conditions, the stitches are all of equal length.

To vary the stitch length, clutch members 2|, 22 are adjusted axially relative to each other. Such stitch length variation is particularly useful in stitching eyelets I9 to folded tape I5. To prevent the eyelets from sliding around on the tape, it is desirable to form a pocket receiving the loops I9 on the legs of the eyelet, and to have the stitches so spaced that each leg of the eyelet has a stitch closely adjacent the leg. The stitches I! of the seam I8, for example, might have a spacing considerably less than the spacing necessar to receive the loops I9 of eyelet between successive stitches. Accordingly, it is desirable to have a longer spacing between the stitches at the eyelet locations.

To achieve this result, cam I9 is secured to gear 66 with thin end I2 as the leading end. The ratchet mechanism I4 is so adjusted that roller 65 reaches the high end II of cam Ill just as an eyelet location on tape I5 reaches the stitching mechanism, gear 66 being continually rotated by shaft I2. As roller 65 rides up the slope of cam I0, clutch member 2| is moved progressively toward clutch member 22, so that the cooperating teeth 33, 34 shove clutch member 22 a little further ahead on each stroke of ratchet mechanism I4. This causes surface 23 to draw tape I5 along a progressively greater distance between each stitch.

As the roller nears the high end of cam III, the stitch spacing just before roller 65 drops off cam end II will be sufiicient to form pockets receiving the loops I9 on the legs of eyelet I 9. When the stitch has been made adjacent the trailing leg of the eyelet, roller 65 drops off cam I0, and clutch member 2| is moved away from clutch member 22. The teeth 33, 34 are now so spaced that there will be no movement of member 22 and tape I5 before the next stitch is made, so that two stitches are made adjacent the trailing leg of eyelet I9. The next succeeding stitches are uniformly spaced, until roller 65 again starts to ride upon cam IIJ.

The extra length stitch spacing to form the eyelet receiving pocket can also be accomplished in a different manner by removing cam ID from gear 66 and reversing the cam so that its high end II becomes the leading end. The stitches are uniform in length until the stitch at the leading leg of eyelet I9 is to be made. The parts are so adjusted that roller 65 mounts up the cam edge I4 and slope I3 to the high point of the cam, moving clutch member 2| toward clutch member 22, so that cooperating teeth 33, 34 shove member 22 ahead an appreciable amount in addition to the amount the latter is moved by clutch member 2| through ratchet mechanism |4. This pulls tape I5 ahead at much larger amount before the stitch is completed at the leading leg of the eyelet, forming a pocket to receive the eyelet loop I9. The next stitch is only slightly less in length to receive the loop IS on the trailing leg of the eyelet. The stitches continue to decrease in spacing as roller 65 rides down cam 10 until the roller passes off low end 12 of the cam. The stitches are then uniform in length until the roller 65 again rides up onto high end E2 of the cam.

Uniform stitch spacing can also be effected by adjusting screw E8 to hold lever 58 in such position that roller 65 no longer engages cam 10. The increase or decrease in stitch length can also be preselected by adjustment of screw 18 so that roller 65 engages or disengages cam H3 at some point intermediate cam ends H and 12.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles thereof, it will be understood that the invention may be otherwise embodied, without departing from such principles.

What is claimed is:

1. Step-by-step rotation apparatus comprising, in combination, a driving shaft; a driven shaft in spaced parallel relation to said drive shaft; means operable by said driving shaft to impart step-by-step rotation to said driven shaft; a clutch having coaxial driving and driven members, said driving member being operable by said driven shaft; interengageable teeth on said members having; cooperating sloping teeth, whereby, relative axial adjustment of said members will vary the degree 'of rotation of said driven member in response to driving impulses from said driving member; a pivotally mounted clutch lever operable to axially adjust said clutch members; cam means rotatable on said driving shaft and engageable with the free end of said lever and selectively operable to activate said lever to axially adjust said clutch members; and a forked arm on said lever fitting over said driving shaft to maintain said lever aligned with said cam means.

2. Step-by-step rotation apparatus comprising, in combination, a driving shaft; a driven shaft in spaced parallel relation to said drive shaft; means operable by said driving shaft to impart step-by-step rotation to said driven shaft: a clutch having coaxial driving and driven members, said driving member being operable by said driven shaft; interengageable teeth on said members having cooperating sloping teeth, whereby, relative axial adjustment of said members will vary the degree of rotation of said driven member in response to driving impulses from said driving member; a pivotally mounted clutch lever operable to axially adjust said clutch members; cam means rotatable on said driving shaft and engageable with the free end of said lever and selectively operable to activate said lever to ax ally adjust said clutch members; a forked arm on said lever fitting over said driving shaft to maintain said lever aligned with said cam means; spring means biasing said lever toward said cam means; and adjustable means limiting movement of said lever toward said cam means.

' tive axial adjustment of said members will vary the degree of rotation of said driven member in response to driving impulses from said driving member; and means for adjusting the relative axial positions of said clutch members.

4. Step-by-step rotation apparatus comprising, in combination, a driving shaft; a driven shaft means operable by said driving shaft for imparting step-by-step rotation to said driven I shaft; a sleeve secured to said driven shaft having diametrically opposite slots therein; a clutch having coaxial driving and driven members, said driven members being rotatable on said sleeve, and said driving member having a hub fitting the projecting end of said driven shaft and spaced fingers engaged in such slots; interengageable teeth on said members having cooperating sloping teeth, whereby, relative axial adjustment of said members will vary the degree of rotation of said driven member in response to driving impulses from said driving member; a pivotally mounted clutch lever operable to axially adjust said clutch members; cam means rotatable on said driving shaft and engageable with the free end of said lever and selectively operable to activate said lever to axially adjust said clutch members; spring means biasing said lever toward said cam means; and adjustable means limiting movement of said lever toward said cam means.

5. Step-by-step rotation apparatus comprising, in combination, a driving shaft; a driven shaft in spaced parallel relation to said driving shaft; means operable by said driving shaft to impart step-by-step rotation to said driven shaft; a clutch having coaxial driving and driven members, said driving member being operable by said driven shaft; interengageable teeth on said members having cooperatin sloping teeth, whereby relative axial adjustment of said members will vary the degree of rotation of said driven member responsive to driving impulses from said driving member; a wheel secured to said driving shaft; a circumferentially tapered arcuate face cam detachably secured to a face of said wheel concentric with said driving shaft; a pivotally mounted clutch lever operable to axially adjust said clutch members; and a roller on the free end of said lever engaging said cam.

LOUIS M. RABINOWITZ.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Breither et al. Nov. 5. 1946 

